Table 1.
Nomenclature of the peptides utilised, with the short names and corresponding amino acid sequences.
Fig 1.
Intracellular delivery of gold nanoparticles assisted by monolayer functionalisation with HA2/TAT peptides.
HeLa cells were incubated with/without 5nm nanoparticles (500nM) functionalised with either capping peptides (CALNN: CCALNN-PEG at a 4:1 molar ratio) or with a combination of dHA2 and/or TAT functional peptides with capping peptides for 3h, fixed and imaged by photothermal microscopy. (A-E) Images of the nanoparticles uptake by HeLa cells, scale bar represents 20μm. Top: photothermal image; bottom: overlay of bright field and photothermal images. (A) Cells without nanoparticles. (B) Cells incubated with CALNN: CCALNN-PEG 4:1 coated nanoparticles. (C) Cells incubated with 10% CCALNN-dHA2 coated nanoparticles. (D) Cells incubated with 1% CALNN-TAT coated nanoparticles. (E) Cells incubated with 10% CCALNN-dHA2 + 1% CALNN-TAT coated nanoparticles. (F) Quantification of the internalisation of gold nanoparticles for the conditions shown in (A-E), measured via the mean photothermal intensities of individual cells (over 40 cells for each condition, each data point represents one cell). All conditions are significantly different from one another except the pair (1% TAT, 10% dHA2-1% TAT). Dataset available on figshare (10.6084/m9.figshare.1088379).
Fig 2.
Effect of PEG on the intracellular localisation of HA2 fusion peptide functionalised gold nanoparticles.
HeLa cells were incubated with peptide-coated 10nm gold nanoparticles (6nM) for 4h, washed thoroughly with PBS, fixed and imaged by electron microscopy. Nanoparticle peptide monolayer composition: (A-B) 10% CCALNN-dHA2 and 90% CALNN, (C-D) 10% CCALNN-dHA2, 20% CCALNN-PEG and 70% CALNN. Arrowheads point toward gold nanoparticles either interacting with vesicular membranes (white), or displaying a cytosolic localisation (black). (E) Density of nanoparticles in endosomes estimated from images shown in (A-B), n = 30; and (C-D), n = 29. The sets of images analysed as well as additional images are available on figshare (10.6084/m9.figshare.875584, 10.6084/m9.figshare.875630).
Fig 3.
Influence of the proportion of CCALNN-dHA2 peptides in the monolayer of gold nanoparticles.
HeLa cells were incubated for 4h with 10nm gold nanoparticles (6nM) coated with a monolayer composed of two different proportions of the peptides CCALNN-dHA2 and CALNN, washed thoroughly with PBS, fixed and imaged by electron microscopy. (A-B) TEM images of the cells incubated with nanoparticle with the following peptide monolayer composition: (A) 50% CCALNN-dHA2 and 50% CALNN, (B) 100% CCALNN-dHA2. Arrowheads point toward gold nanoparticles either interacting with vesicular membranes (white) or displaying a cytosolic localisation (black). (C) Density of nanoparticles in endosomes estimated from images shown in (A) (n = 10, middle) and (B) (n = 10, right); quantification for 10% CCALNN-dHA2 (left) is the same as in Fig. 2E (left). The sets of images analysed are available on figshare (10.6084/m9.figshare.875545, 10.6084/m9.figshare.875477).
Fig 4.
Attachment of HA2 to gold cores via the C-terminus versus N-terminus.
HeLa cells were incubated for 4h with 10nm gold nanoparticles (6nM) capped with peptide monolayers of different compositions, fixed, and imaged by electron microscopy. Nanoparticle peptide monolayer compositions were: (A) 20% CCALNN-HA2 and 80% CALNN; (B) 20% HA2-NNLACC and 80% CALNN; (C) 50% CCALNN-HA2 and 50% CALNN; (D) 50% HA2-NNLACC and 50% CALNN. Arrowheads indicate particles around or outside endosomes. Additional images are available on figshare (10.6084/m9.figshare.874219, 10.6084/m9.figshare.874153, 10.6084/m9.figshare.874033, 10.6084/m9.figshare.873852).